Staying up late disrupts adolescents’ circadian rhythms, increasing carb intake and sedentary tendencies, a study finds.

Summary: A new study presented at the SLEEP 2024 annual meeting found that circadian misalignment, common among adolescents, is linked to higher carbohydrate consumption and increased sedentary behavior. The research showed that a later sleep schedule is significantly associated with greater carbohydrate intake and more sedentary behavior, even after adjusting for various factors. The study involved 377 adolescents who underwent sleep and physical activity assessments. Researchers emphasized the importance of proper circadian alignment for adolescent health, suggesting that interventions targeting dietary choices and physical activity should consider sleep-wake cycle variability.

Key Takeaways:

  • Adolescents with later sleep schedules tend to consume more carbohydrates, with irregular sleep timing partially explaining this relationship.
  • A later sleep schedule is also linked to increased sedentary behavior, independent of demographics, sleep disorders, and insufficient sleep.
  • Proper circadian alignment is crucial for adolescent health, and interventions addressing poor diet and sedentarism should consider the impact of sleep-wake cycle variability.

A new study found that circadian misalignment, which is highly prevalent in adolescents, is linked with carbohydrate consumption and sedentary behavior in teens.

Results, presented at the SLEEP 2024 annual meeting, show that a later sleep schedule was significantly associated with greater intake of carbohydrates, and this relationship was partially explained by irregular sleep timing. A later sleep schedule also was associated with greater sedentary behavior, even after adjusting for variables such as demographics, sleep disorders, and insufficient sleep.

“Delaying sleep schedules is normal during puberty and adolescence; however, some adolescents delay their sleep schedule to an extent that they become misaligned with the day-night cycle, their social schedules, and responsibilities,” says principal investigator Julio Fernandez-Mendoza, PhD, a professor and clinical psychologist at Penn State College of Medicine, in a release. “Our data supports that this lack of alignment may be associated with inadequate diet and physical activity, further contributing to the obesity epidemic and poor cardiometabolic health.”

Study Details

The study involved 377 adolescents from the Penn State Child Cohort who had a minimum of three nights of at-home actigraphy and one night of in-lab polysomnography. 

These tests helped calculate their sleep midpoint and sleep regularity. Physical activity was also measured by actigraphy, and carbohydrate intake was assessed using a survey.

Implications for Teen Health

According to the American Academy of Sleep Medicine, sleep is essential to health, and healthy sleep requires adequate duration, good quality, appropriate timing and regularity, and the absence of sleep disturbances or disorders. A delayed sleep schedule, characterized by sleep timing that is later than conventional or socially acceptable timing, is more common among adolescents and young adults.

Fernandez-Mendoza notes in a release that proper circadian alignment is necessary for the health of adolescents.

“Circadian misalignment of the sleep-wake cycle, and its associated variability in sleep duration, should be an integral part of interventions targeting poor dietary choices and sedentarism in youth,” Fernandez-Mendoza says in a release.

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